1. Field of the Invention
The present invention relates to a network monitoring system, a monitored controller, and a monitoring controller, and more particularly to a network monitoring system, a monitored controller, and a monitoring controller with increased efficiency in network monitoring activities.
2. Description of the Related Art
A variety of user needs for telecommunications services have driven the evolution of today""s network infrastructures, increasing their complexity and expanding their scale. In such circumstances, operations and maintenance of communication links require highly sophisticated network monitoring technologies which collect necessary data from network equipment and provide the maintenance engineers with useful information for their activities. More specifically, the network monitoring system should collect alarms and other status information from many pieces of transmission equipment deployed across a large geographical area, concentrate such information at a maintenance center, discover and isolate the problem, and inform the maintenance engineers of the location of the problem in a prompt and reliable manner.
Take an Asynchronous Transmission Mode (ATM) network for instance. In conventional monitoring systems, a point-to-point connection is established between a monitoring station and each ATM network device to be monitored, so that status information messages will be collected through the established connection. The monitoring station communicates with ATM network devices by using the Simple Network Management Protocol (SNMP), which is originally designed for TCP/IP network management. The SNMP protocol defines some techniques called xe2x80x9cpollingxe2x80x9d and xe2x80x9ctrapxe2x80x9d for handling of status information. Conventional network monitoring systems use this polling, trap, or both.
In a polling-based system, the network monitoring station collects status information from ATM network devices by transmitting query messages at regular intervals to request them to send back their local administrative information, including device configuration, functional status, and statistics. The network monitoring station then detects configuration changes and/or status changes by comparing the present information with the previous information. In this way, the polling-based system can collect administrative information in a reliable manner. This system, however, repeats such data collection at predetermined intervals, regardless of the presence of actual status changes in each individual ATM network device, and thus it often produces unwanted, redundant network traffic over the UNI and NNI networks. As such, conventional polling-based systems have a problem concerning the efficiency in the usage of network bandwidth.
On the other hand, in a trap-based network monitoring system, each occurrence of status changes will propagate to the network monitoring station in the form of an information message, or trap. An advantage of this system is the timeliness of administrative information delivery. However, since the message transmission process in this system involves no acknowledgement sequence, it may happen that a trap will be lost in the process of delivery because of traffic congestion or other problem conditions. It is impossible, in such a case, for the network monitoring station to know the occurrence of a status change in that ATM network device. A reliability problem of this kind exists in the conventional trap-based network monitoring systems. Furthermore, when a plurality of network monitoring stations are deployed, the ATM network devices should send the same trap messages to each individual monitoring station. This imposes additional workloads on the ATM network devices, as well as producing increased traffic over the NNI network.
As a compromise between the two approaches described above, there is another system that uses simple traps to detect the occurrence of each event and then performs polling operations to collect further information, subsequently to the detection. Conventionally, however, this architecture takes no consideration about the loss of trap information. Further, this system still produces redundant traffic since it mainly uses polling techniques to collect status information.
Taking the above into consideration, a first object of the present invention is to provide a network monitoring system which is designed to alleviate the workload imposed on network devices to be monitored, eliminate redundant network traffic, improve the quality of data transmission, and increase the efficiency in network monitoring activities.
Moreover, a second object of the present invention is to provide a controller to be monitored with increased efficiency in network monitoring activities.
Furthermore, a third object of the present invention is to provide a monitoring controller with increased efficiency in network monitoring activities.
To accomplish the first object, according to the present invention, there is provided a network monitoring system which employs a plurality of monitoring stations to observe status of controllers on a network. This network monitoring system comprises the following elements:
(a) a monitored controller being observed by the plurality of monitoring stations, comprising
a connection set-up unit which establishes a point-to-multipoint connection, and
a status message transmission unit which transmits status messages through the point-to-multipoint connection upon detection of a status change in the monitored controller;
(b) a broadcast unit which broadcasts the status messages through the point-to-multipoint connection; and
(c) a plurality of monitoring controllers, coupled to the plurality of monitoring stations, each of which comprises a status message format conversion unit to convert the status messages received from the broadcast unit to a format suitable for the monitoring station being coupled thereto.
To accomplish the second object, according to the present invention, there is provided a monitored controller being observed by monitoring stations in a network monitoring system. This monitored controller comprises the following elements:
(a) a connection set-up unit which establishes a point-to-multipoint connection to the monitoring stations via a broadcast unit; and
(b) a status message transmission unit which transmits status messages through the point-to-multipoint connection upon detection of a status change in the monitored controller.
To accomplish the third objects, according to the present invention, there is provided a monitoring controller coupled to a monitoring station in a network monitoring system. This monitoring station comprises the following elements:
(a) a status message reception unit which receives status messages sent from a network device being monitored;
(b) a status message format conversion unit which converts the status messages received by the status message reception unit to a format suitable for the monitoring station being coupled thereto; and
(c) a status message transmission unit which transmits to the monitoring station the status messages converted by the status message format conversion unit.
The above and other objects, features and advantages of the present invention will become apparent from the following description when taken in conjunction with the accompanying drawings which illustrate preferred embodiments of the present invention by way of example.